Proceedings - Teaching and Learning Centre - Simon Fraser ...

Fraser River Action Plan 3rd Research Workshop
Research Forest of UBC in August - September, 1995. Sixteen plexiglass troughs of about 2.5 m length and 25
cm width were supplied with running water diverted from Mayfly Creek via a pipeline and distribution box.
Flow was adjusted such that each trough received approximately 0.1 L/s of water. Heavy metals were added as a
constant ratio of dissolved Cu:Mn:Zn:Pb, but at different doses from Marriot bottles at the head of each trough.
The ratio of metals and range of doses were based on data for the Brunette River from Dr. Ken Hall.
A suite of biological and chemical parameters were measured as response variables. The concentration of heavy
metals in effluent water was measured. Samples of leaf tissue which might be an adsorption surface were
collected for analysis. Other measures included:
• microbial respiration rate on leaf tissue from each trough;
• emigration or “drift” rate of macroinvertebrates before and during treatment;
• benthos at the end of the experiment; and,
• algae — as chl a concentration and as relative abundance.
Most of these data sets are nearing completion. We would like to repeat this experiment with greater control over
dosing rates and metal speciation in the test mixture. Repeating the experiment would also increase the overall
statistical power of the experiment when combined with the 1995 results.
Next Steps
We need to put all these data together for publication. The direct comparison of experimental results to the
community structure of lower Fraser basin streams will allow us to test the prediction that the species that show
sensitivity to heavy metals additions are those that are absent from natural streams.
We have now compiled a large data set on stream communities in the lower Fraser basin including urban,
agricultural, forested and montane streams. These data will be compared to determine a series of patterns that
have been predicted based on the type of environmental perturbation. Ordination and other gradient analyses will
be used to extract these patterns from the data set for community configuration and test for associations with
characteristics of the channel and catchment.
It appears that some of the lower Fraser basin sites in the Salmon River drainage have fish assemblages similar
to those of streams of mostly undeveloped drainages. Thus, the Salmon River sites can be considered as a
reasonable reference drainage against which other catchments can be compared, but there are limitations to the
degree of inference that can be made from such comparisons. Having further reference sites from drainages other
than the Salmon River would permit one to make more definitive statements about the historical state of small
streams rather than being constrained by the uncertainty about the uniqueness of the Salmon River watershed.
These data will only be useful as a baseline reference if further studies are continued to estimate the degree of
variation attributable to several sources to resolve the true long-term mean condition of the system. Our studies
are snapshots, but inclusion of a large number of sites reduces that problem somewhat although they can still be
temporally autocorrelated signals. The indication that some sites in the Lower Mainland are “healthy” provides a
useful point of reference for future studies.
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